For reeling a continuous paper web, it is common to use a reel-up in which the paper web is reeled onto reeling drums to make finished paper reels. A traditional reel-up normally has a stand that comprises two longitudinally extending, parallel stand members, between which a powered surface winding drum is rotatably arranged. The surface winding drum is operated at a peripheral speed corresponding to the speed of travel of the paper web running over the surface winding drum. To maintain continuous production of paper reels, two separate reeling systems that cooperate with each other are normally used. These consist of a primary system, in which a number, usually a small number, of turns of the paper web is first wound onto an empty reeling drum, and a secondary system that receives the commenced paper reel from the primary system. The reeling of the paper web onto the reel is then continued in the secondary system to produce a finished paper reel. The primary system normally has a pair of pivotable primary arms arranged at either end of the surface winding drum. The described type of reel-up typically also has a pair of lowering arms pivotably journalled to a drum stock arranged above the surface winding drum. When the paper reel being reeled in the secondary system has reached a certain predetermined size, an empty reeling drum is lowered with the aid of the lowering arms from the drum stock to the primary arms. The secondary system, which is located downstream of the surface winding drum, comprises either a pair of secondary carriages each arranged to be linearly moveable along a stand member, or a pair of secondary arms each pivotable about a bearing. Each secondary carriage or secondary arm has a gripper for receipt of the reeling drum from the primary arms and for support of the same during reeling. The construction of the reel-up described here precludes a relatively large space above and nearby the surface winding drum from being used for any other installations, because of the necessary pivoting movements of the lowering arms. A reduction in the space required by the lowering arms would mean that the dimensions of the reel-up could be reduced in an advantageous way or, alternatively, that the space could be used for other important installations.
As reel-ups become ever faster, it also becomes increasingly important that a new reeling drum can be transferred from the drum stock into contact with the surface winding drum in a quick but nevertheless completely safe and reliable way. Endeavors have been made with some known reel-ups to increase safety by letting the primary arms themselves grip the reeling drum in the drum stock directly and then hold the reeling drum during the subsequent transfer down to the surface winding drum, thereby eliminating the lowering arms and the necessity of making a transfer from lowering arms to the primary arms. The time required for the transfer of an empty reeling drum represents a time during which optimal production of reeled-up paper cannot be obtained, which constitutes a problem to which no satisfactory solution has been found. This is especially true when it is considered that the reeling drum, before it can be brought into contact with the surface winding drum, must first be accelerated from stand-still up to the peripheral speed of the surface winding drum. A separate starting device arranged at the side of the surface winding drum is usually used for this acceleration. It would thus constitute a very substantial advantage if the acceleration of the reeling drum could be started and completed during the actual transfer of a new reeling drum from a drum stock, as production would then increase. Several known reel-ups have so far been constructed to at least endeavor to reduce one or more of the above-mentioned problems. No reel-up has yet managed to solve all the described problems in a satisfactory way.
For instance, EP-Al-350 212 discloses a reel-up with a primary system that comprises two pivotably arranged primary arms, which themselves collect each new reeling drum from a drum stock arranged above the surface winding drum, convey the reeling drum to abut the surface winding drum and, after the reeling drum has had a certain number of turns of the paper web wound onto it, deliver the reeling drum to a secondary system for continued reeling. An acceleration of the reeling drum is carried out before it is brought to abut the surface winding drum, but it is not specified how or where this takes place. A disadvantage with this reel-up is that the primary arms, which are pivoted about a fixed pivoting point, have a constant radial length and the position of the grippers on the primary arms is fixed. The primary arms thus have an invariable reach, determined by the fixed turning radius of the arms. Consequently, the primary arms can compensate only for very small variations in the "collecting position" of the new reeling drums, successively fed to the lowermost point in the drum stock. For the primary arms to be maneuverable between the drum stock and the surface winding drum, the stock must be situated beyond the turning radius. This means that the location of the drum stock becomes completely dependent on the fixed reach of the primary arms. Furthermore, primary arms with an invariable reach greatly reduce the ability to let the paper reel continue to build up in the primary system because the primary arms must deliver the reeling drum and the paper reel commenced thereon to the secondary system within a very limited space adjacent to the surface winding drum. This known construction also has a relatively large space where the primary arms are pivoted within which no other fixed installations can take place.
U.S. Pat. No. 3,877,654 discloses a reel-up with primary arms that have beams on which linearly moveable carriages are mounted. The carriages are provided with grippers for reeling drums. Each carriage is arranged to be conveyed along its beam with the aid of an actuator from a first position in which a reeling drum is gripped in a drum stock arranged above the surface winding drum, to a second position in which the reeling drum is brought into contact with the surface winding drum. The free ends of the beams are located beyond the carriages when the carriages are in the first position for collecting a reeling drum from the drum stock. Accordingly, the reel-up does not reduce the requisite working space in any appreciable way compared to the reel-ups that use lowering arms. The acceleration of the reeling drum takes place only after the reeling drum has been conveyed from the drum stock all the way to a position immediately adjacent to the surface winding drum, and therefore no tangible time savings are made, despite the elimination of the lowering arms. A further disadvantage is that roller bearings are arranged to guide the carriage along the beam, and hence it is difficult to control the position of the carriage along the beam with any great precision. This can result in unsatisfactory control of the nip pressure between the reeling drum and the surface winding drum.